<!DOCTYPE html><html xmlns:th="http://www.thymeleaf.org/" lang="en"><head>    <meta charset="UTF-8">    <title>用户登录</title></head><body><h1>用户登录</h1><form action="/doLogin" method="post">    用户名：<input type="text" name="username"> <br>    密码：<input type="text" name="password"><br>    <input type="submit" value="登录"></form></body></html>